There are a total of `numCourses` courses you have to take, labeled from `0` to `numCourses - 1`. You are given an array `prerequisites` where `prerequisites[i] = [ai, bi]` indicates that you **must** take course `bi` first if you want to take course `ai`.
- For example, the pair `[0, 1]`, indicates that to take course `0` you have to first take course `1`.
Return `true` if you can finish all courses. Otherwise, return `false`.
Examples
Example 1
Input:
numCourses = 2, prerequisites = [[1,0]]Output:
trueThere are a total of 2 courses to take. To take course 1 you should have finished course 0. So it is possible.
Example 2
Input:
numCourses = 2, prerequisites = [[1,0],[0,1]]Output:
falseThere are a total of 2 courses to take. To take course 1 you should have finished course 0, and to take course 0 you should also have finished course 1. So it is impossible.
Constraints
- •
1 <= numCourses <= 2000 - •
0 <= prerequisites.length <= 5000 - •
prerequisites[i].length == 2 - •
0 <= ai, bi < numCourses - •
All the pairs prerequisites[i] are unique.
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